1. Field of the Invention
The present invention relates to a partition structure for absorbing impact energy and an installation structure for an installation part.
2. Description of the Related Art
Conventionally, in vehicles such as motor vehicles, a partition is provided to partition a room. JP 11-139348 A discloses a technology for suppressing deformation against an external force by forming a partition integrally with beads (folding or channel) to increase a stiffness of the partition itself.
For example, there may be a case that a cargo moves forward by an inertial force at a frontal collision or a quick service (strong braking) and collides with the partition. However, in the structure of which stiffness itself is enhanced, when the cargo collides with the partition, if the impact exceeds a limit in strength, the partition is destroyed at a burst. Then, fragments of the partition may fly toward a crew (front side of the partition). This is a problem.
On the other hand, to install an installation part at an installation position of an installation target member, generally a bolt and a nut are frequently used. JP 6-300023 A discloses this in FIG. 1.
In an installation unit for a counter weight used in, for example, a construction equipment disclosed in JP 6-300023 A in FIG. 1, the nut may rotate together with the bolt when the bolt is rotated to engage with the nut to fix an installation part (counter weight) to an installation target member (frame). To avoid the rotation of the nut, the installation unit is formed integrally with a jam plate to prevent the nut from rotating.
In the installation unit for installing the counter weight in, for example, a construction equipment disclosed in JP 6-300023 A in FIG. 1, the jam plate which is bent in L-shape from a washer plate to abut a place on an outer circumferential surface of the nut. This prevents the nut from rotating together with the bolt.
In such the bolt and the nut, when the bolt is engaged and screwed with the nut, the rotation of the nut together with the bolt can be prevented. However, when the nut on an opposite side of the frame is engaged and screwed with the bolt, the nut may drop if an installation operation is performed with the nut being holed by a hand.
Therefore, when the nut which is one fixing member is engaged and screwed with the bolt which is the other fixing member, there is a problem in that a workability is low.
Particularly, in a case that a size of the installation part (counter weight) or the installation target member (frame) is large, when an operator holds the bolt on a top surface side and the nut on the back surface by both hands simultaneously, it is difficult to fasten the bolt because the operator cannot reach the nut by hand.